Liquid fuel is typically supplied to the combustor section of a gas turbine engine by a plurality of fuel nozzles discharging atomized liquid fuel into a combustion chamber or the like. Prior art arrangements are disclosed in U.S. Pat. No. 4,365,470 to Matthews et al, U.S. Pat. No. 4,322,945 to Peterson et al, and U.S. Pat. No. 3,273,343 to Cretella.
In typical gas turbine engines, the fuel nozzle extends through an opening in the combustion chamber, discharging a spray of liquid fuel into the chamber interior wherein it is mixed with combustion air and reacted at high temperature. In order to permit convenient servicing of individual fuel nozzles, the nozzles and the combustion chamber are typically supported independently within the engine, with the fuel nozzles additionally being located in a region of relatively cool temperature in order to prevent overheating of the fuel flowing to the nozzle discharge.
Such design features, in combination with the high temperature of the combustion reaction, result in differential thermal expansion between the combustor chamber and the fuel nozzles. Such expansion is accommodated through the use of a movable guide structure disposed in the wall of the combustion chamber which receives the fuel nozzle. These guide structures, as shown in the referenced patent documents, may serve a dual function by not only controlling the amount of air admitted into the combustion chamber adjacent the fuel nozzle, but additionally protecting the nearby chamber wall from the high temperature combustion reaction.
Prior art nozzle guide structures are typically complex, having airflow paths defined therein and being engaged with the combustion chamber walls by a variety of sliding clip or channel arrangements. These complicated structures can be difficult to assemble and repair both in the production shop and in the field. Moreover, prior art nozzle guide structures have tended to concentrate bearing forces on limited areas of the combustor wall leading to premature wearing and reduced service life for the guide structure and the chamber wall.
What is needed is a nozzle guide structure which is both simple in itself, simple in its engagement with the wall or bulkhead of the combustion chamber, and which provides the necessary thermal protection to the combustion chamber wall adjacent the fuel nozzle.